Heating circuit control for electric ranges



April 24, 1951 w. R. McDowr-:LL 2,550,579

HEATING CIRCUIT CONTROL FOR ELECTRIC RANGES Filed Oct, 27, 1948 A 2 Sheets-Sheet 1 April 24, 1951 w. R. MCDOWELL HEATING CIRCUIT CONTROL F'OR ELECTRIC RANGES Filed oct. 27, 1948 2 sheetsA-Sheet 2 oFF WARM

LOW

In 1/erz 1faef ufall.

HIGH

Patented Apr. 24, 1951 UNITED STATES PATENT OFFICE HEATING CIRCUIT CONTROL FOR ELECTRIC RANGES Walter R. McDowell, Westchester, Ill., assignor to Hotpoint Inc., a corporation of New York The present invention relates to heating circuit controls for electric ranges, and more particularly to improved controls of the type disclosed in the copending application of Leo F'. Berg and Walter R. McDowell, Serial No. 17,248, filed March 2.6, 1948, now Patent No. 2,530,643.

In the Berg and McDowell application mentioned there is disclosed an electric range provided with a cooking top carrying a surface heating unit and a backsplasher carrying a manually operable control switch of the rotary multipleposition type for selectively setting the heating control connections of the heating unit with respect to an associated source of current supply. Also this electric range comprises a cooking vessel carrying a thermal responsive device operative in response to a predetermined cooking condition in the vessel, a relay operative to change the heating control connections of the heating unit with respect to the source, and a control circuit including the device for operating the relay.

In the operation of this electric range the control switch is rst set to its high control position and the vessel and its contents are placed upon the surface heating unit, whereby the vessel and its contents are heated at the high rate. When a cooking temperature is reached by the contents of the vessel, the thermal responsive device is operated automatically to govern the control circuit so as to effect operation of the relay. Upon operating the relay controls its own contacts in order to interrupt the high rate heating connection to the surface heating unit and then to complete a low rate heating connection to the surface heating unit, thereby to prevent vigorous boiling of the contents of the vessel.

While this heating control circuit arrangement is entirely satisfactory in operation, it renders an indicator associated with the control switch ineffective to indicate the actual heating rate of the surface heating unit, when the relay occupies its operated position. In other words, the operation of the relay to change the heating connections from the high rate to the low rate does not change the position of the control switch, so that the associated indicator erroneously indicates the high heating rate after the low heating rate is effected. This peculiar operation of this heating control circuit arrangement is confusing to the user of the electric-range as she relies upon the indicator and erroneously contends that the arrangement is working improperly.

Accordingly, it is a general object of the present invention to provide in an electric range, a heating control circuit arrangement comprising a single control switch that is selectively set both manually and automatically for the purpose of selectively controlling the associated heating unit so that the indicator associated with the control switch always indicates the actual heating control connection of the heating unit with respect to the associated source of current supply.

Another object of the invention is to provide in an electric range, an improved heating control arrangement utilizing a manually operable push button switch and a motor for operating a given one of the push buttons in order to obtain an automatic control of the associated heating unit.

Another object of the invention is to provide in the combination of an electric range and a cooking vessel, an improved automatic arrangement controlled in accordance with the cooking condition in the vessel for governing the heating rate of the heating unit arranged in heat eX- change relation with the vessel.

A further object of the invention is to provide in the combination noted, an improved quickdetachable control circuit arrangement between the electric range and the cooking vessel.

Further features of the invention pertain to the particular arrangement of the elements of the electric range and of the control circuit, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which Figure 1 is a front perspective view of an electric range and a cooking vessel supported by one of the heating units carried by the associated cooking top and embodying the present invention; Fig. 2 is a diagrammatic illustration of theheating and control circuits and facilities incorporated in the electric range and in the cooking vessel; Fig. 3 is a greatly enlarged sectional view, taken through the backsplasher of the electric range in the direction of the arrows along the line 3-3 in Fig. 1, illustrating the push button control switch and the electroresponsive operating motor therefor; Fig. 4 is a greatly enlarged end view, similar to Fig. 3, partly broken away, taken in the direction of the arrows along the line 4--4 in Fig. 1, illustrating the quickdetachable electric cable connector mechanism that is provided for connecting the cooking vessel into the control circuit when automatic heating control of the associated heating unit is desired;

Aling top I3, as illustrated in Fig. 3. indicated the backsplasher I4 is of lhollow conand Fig. is a greatly enlarged bottom view of the push button control switch, taken in the direction of the arrows along the line 5 5 in Fig. 3.

Referring now to Fig. l of the drawings, there is illustrated the combination of an electric range I0 and a cooking vessel I I embodying the features of the present invention. More particularly, the range I0 comprises an upstanding frame or body I2 provided with a substantially horizontally disposed cooking top I 3 terminating adjacent to the rear thereof in an upwardly vextending 4backsplasher I4. The body I2 comprises ian ovendisposed in the right hand portion thereof below the cooking top I3 and having anfopen'front closed by a suitable door I5,'thedoor I5lbeing hinged adjacent to the loweredgethereof in :a manner not shown. Also the body I2 comprises a. storage space disposed in the left handsportion thereof below the cooking top I3 and receiving movable-drawer structure I6. The lefthand'upper surface of the cooking top i3 carriesfour Asurface heating-units-Il, I8, I9'and 2U. The-'oven Y is provided 'with :a heating circuit'including a push'button controlswitch 2|; andthe heating -units .II, I8, I9 and 2U are respectively provided with :heating circuits respectively including push button control switches 23,24 and 25, the

push button control switches 2I to25, inclusive, being mounted lupon the backsplasher I4. 'The :heating units I1, I8, I9 andZ are arrangedtin la"substantiallyrectangular pattern upon the up- \perssurface of the cooking'top I3 and arehereinafter respectively referred to as the left front, `the left rear, the right rear and the'right front lsurface `heating units. vMore particularly, the 'backsplasher I4 has `a centrally disposed depression'ZB'formed therein and disposed between the left -hand end 2l and the right hand end 28 thereof. Anelongated window '29 is arranged vin the upper portion ofthedeprcssion'25` into which a suitable pane of transparent material-38, such as glass, or the like, is mounted, an -elongated lelectric lamp '3| being disposed behind the pane -30 forrthe purpose of illuminating the front of the backsplasher I4, and consequentlythe cook- As previously7 struction and the'switches 22, '23, 24, 25 and 2I Y are preferably arranged in a straight line in the -depression 26 below the pane as clearly shown in Figs. 1 and 3.

As diagrammatic'ally illustrated, the cooking *vessel I I is preferably of the construction and arrangement disclosed in the previously-mentioned 'l Berg and McDowell application, the vessel iI being formed of aluminum, or the like, and ycomprising a substantially cylindrical side wall 4I provided with an open topand ajconnecting bottom wall. The open top of the side wall 4I is provided with anoutwardly ared rim 42 that is adapted internally to receive the outwardly flared rim of a cooperating removable cover 43,

also formed of aluminum, or the like. The ves- Vsel I I comprises a hollow `handle 44 the inner end "of which terminates ina hollow housing 45 that is detachably secured to the cylindrical side wall '4I and the outer end of which terminates in a hand-gripping portion 46 formed of any suitable thermal and electrical insulating material.

I Within the housing 45 there is mounted a thermal :responsive device `41 disposed in good heat eX- 'ichange relation with the cylindrical side wall 4I of the vessel II when the housing 45 isysecured 'ther-etc. Also a control switch 48 is arranged Al l) within the housing 45 and operatively connected to the thermal responsive device 4l. In the extreme outer end of the hand-gripping portion 46 of the handle 44 a cavity 49 is provided, in which there is supported a plug 50, the plug 5D being electrically wired through the handle 44 to the control switch 48. In the arrangement the plug :5D ,is 'disposed entirely withinthe cavity 4S and the plug 5I] Vis connected in water-tight relation with the handle 44 in order to prevent the admission of water into the hollow structure of the handle 44. .-Also the cavity 49 is adapted to receive-a socket 5I forming a part of the control circuit, described more fully hereinafter, which .socket"5I when-supported in the cavity 49 makes Vgood electrical Vcontact with the plug 5d for the purpose ofconnecting the control switch 48 into the control circuit. When it is necessary to wash sthe Vvessel II the handle 44 may be detached therefrom, or the whole assembly may be washed .asa unit; all as :disclosed inthepreviouslymentionedBerg and McDowell application. y

Preferably each of the controlfswitches 2I, 22,

123,24 and 25 is kof the manually operable .push button type disclosed in U. SiPatent No. 2,4313904,

granted on December 2, 1947, to John L. Andrews. :For example, the control switch 24 individual to rthe right rear surface heating unit I9 comprises,

comprises the control positions high, second,

Awhile the 'jackets 63D, etc., project rearwardly `through'guide openings formed in the housing 62. As illustrated inFig. 3, thepush buttons E3, etc., Vproject through a laterally extending slot 63a Aformed in the base 60, thence through a laterally extending registering slot I 4a formed in the front vof the backsplasher I4 and ultimately through a laterally extending slotia formed in a laterally extendingtrim member 89 secured to the front ofthe backsplasher vI4 within .the depression 26. Accordingly, in the push button switch 24 the individual push buttons 63, etc.are readily accessible from the front of the vbacksplasher I4 and may be readily operated manually; while the trim member 69 trims the front of the backsplasher "I4 concealing the openings I4a, etc., ,formed ytherein through which the push buttons of the individual'switches 24, etc., project.

The insulating housing 62 is removably secured to the bracket structure 6I by a pair of screws 1U, and the rear end thereof supports three laterally spaced-apart'upper line terminals 1I-and three laterally spaced-apart lower control lterminals 12, the terminals 'II and 'I2 being utilized for the purpose of establishingconnections through the switch 24 between a source of current supply and the surface heating unit I9, as explained more fully hereinafter. The housing 62 supports both stationary and movable contact structure, as well as control mechanism selectively operated by the individual push buttons 63, etc., for the purpose of operating the contact structure into the various circuit control positions, and interlock mechanism for the purpose of preventing simultaneous operation of two of the push buttons 63, etc.; all as disclosed in the Andrews patent mentioned. For example, when the off push button 68 occupies its inwardly disposed operated position the heating connections to the right rear surface heating unit I9 are interrupted and the remainder of the push buttons 63, etc., occupy their outwardly disposed unoperated positions. At this time when the high push button 63 is moved to its inwardly disposed operated position, the off push button 88 is iirst moved to its outwardly disposed unoperated position by the interlock mechanism and simultaneously the control mechanism actuates the movable contact structure with respect to the stationary contact structure in order to establish the high heating control circuit between the right rear surface heating unit I9 and the source of current supply, as described more fully hereinafter.

Each of the jackets 63h, etc., of the push buttons 63, etc., has an opening 63e formed in the lower surface thereof that is adapted to receive an arm of abell-crank for the purpose of effecting motor operation of the corresponding push button 63, etc. In the present example the bellcrank arrangement is operatively associated with the low push button 66, and specically the base 60 carries a rearwardly extending tab 13 that is disposed adjacent to and below the low push button 66,'the tab 13 carrying a pivot pin 14 upon which the bell-crank is pivotally mounted. More speciiically, the bell-crank 15 comprises an upwardly directed arm 16a that projects through the opening 66e in the jacket 66h of the low push button 66 and a rearwardly extending arm 18h. Also the base 6I] carries adjacent to the lower end thereof a rearwardly extending substantially U- shaped bracket 11 upon which there is mounted an electro-responsive motor 18. More particularly, the motor 18 comprises a solenoid or winding 1S and field structure provided with an associated armature 80 that is operatively connected by a link 8l to the outer end of the arm 16h of the bell-crank 15. Thus it will be understood that the low push button 66 may be operated either manually from the iront of the backsplasher I4 or automatically by the motor 18. More specifically, when the winding 19 of the motor 18 is energized the armature 8] is drawn downwardly rotating the bell-crank 15 in the clockwise direction, as viewed in Fig. 3, about the pivot pin 14 and moving the low push button E6 from its unoperated position into its operated position. Of course, it will be understood that when the low push button 55 is operated either manually from the front of the backsplasher I4 or automatically by the motor 18 the push button switch 24 is operated into its low heating control position.

Further the push button switch 24 comprises a metallic hood 82 disposed above the jackets 63h, etc., and carrying an electric lamp 83 adapted to project illumination downwardly onto the blocks 63a, etc. Preferably each of the control switches 24, etc., embodies the color indicator arrangement for indicating the operated position thereof disclosed in U. S. Patent No. 2,437,555, granted on March 9, 1948, to Gregory L. Rees. Specifically, a transparent color card is arranged below the lamp 83 and above the jackets 63h, etc.; which color card 85 carries a series of individually colored transparencies respectively associated with the blocks 63a, etc., and respectively indicating by color the control position of the push button switch "24; al1 as disclosed in the Rees patent mentioned. More particularly, the colored transparencies carried by the color card 85 and respectively associated with the push buttons 63, 64, 65, 66 and 61 are red, yellow, purple, green and blue and are respectively brought into operative relation with respect to the blocks 63a, etc., when the respective push buttons 63, etc., are operated. Thus when the high push button 63 is operated the lamp 83 is illuminated and the block 63a is moved into operative relation with the red transparency carried by the color card 85 so that the extreme outer end of the high push button 63 glows red indicating that the push button switch 24 occupies its high control position. rl'he second push button 64 glows yellow when it is operated, and the other push buttons 65, 66 and 61 respectively glow in the corresponding colors purple, green and blue, when they are individually operated. Thus a color indicator is incorporated in the push button switch 24 in addition to the physical positions of the push buttons 63, etc., for the purpose of indicating the different control positions thereof.

The right hand end 2S of the backsplasher I4 carries a lower electrical receptacle 98, illustrated in Figs. 1 and 4, that may be utilized for the purpose of receiving the plug of a small electrical appliance, such, for example, as an electric coffee pot; while an opening 28a is formed in the-right hand end 28 of the backsplasher I4 above the receptacle 9i? and covered by an associated ornamental trim element 92. The trim element 92 has a centrally disposed opening 92a formed therein through which a flexible connector or cable 93 extends, the outer end of the cable 93 carrying the socket 5I. A reel mechanism 94 is mounted behind the right hand end 28 of the backsplasher I4 and receives the inner end of the cable 93. The reel mechanism 84 may be of any conventional type, such, for example, as of the window-shade construction, capable of paying-out a fixed predetermined length of cable 93 and of retracting the payed-out length or" cable S3 when the socket 5l is released. More particularly, the reel mechanism Q4 normally biases the cable S3 into its retracted position causing the socket 5I to be drawn into contact with the front of the trim element S2, the socket 5I being suiiiciently large to prevent passage thereof through the opening 92o: formed in the trim element 92. At this time the socket 5I engages the front of the trim element S2 and is completely out of the way with respect to the cooking top i3. When it is desired to use the cooking vessel I I the socket 5I is seized and pulled forwardly; whereby the reel mechanism 94 pays-out the required amount of the flexible cable S3 so that the socket 5I may be readily placed into the recess 49 provided in the end of the handgripping portion 46 of the handle 44 for the purpose of establishing electrical connection between the socket 5I and the plug 5e. As the cable 93 is payed-out a stop arrangement, not shown, incorporated in the reel mechanism 34 restrains the cable 93 in its payed-out position; however, when the socket 5I is detached from the plug 50 and released the stop arrangement is released and the cable 83 is again retracted bringing the socket 5i into engagement Awiththe trim element 92. :The reel mechanism 8 4 iis arranged to pay-out only -a limited length Aof the cable :93; :whereby Ythesoclret 5| may be -readilyattached tothe plug 50 and the vessel -moved by the hand-gripping portion 46 of the handle 44 into heat exchange vrela-tion with -respect to the rightrear surface yheating unit |0.

Howeven 4this length of the cables?. vis not suicient to permitsthe cooking vessel to be placed pin heat exchange relation -with -anyfone of lthe --other surface heating Y.units H, |-8 and 20.

Thus Iit vwill be understood that when the socket 5| is attached to the plug 50 the cooking vessel must be used only upon the right `rear 4surface heating unit |9, as .the length of cable 93 will not `reach any one of the other surface heating-units. Finally, the reel mechanismV 94 Ycomprises terminals that are employed for the purpose of lconnecting the inner end of Ithe lcable -33 into the associated control circuit. Considering now the heating and control cir- .cuit arrangement in greater detail, the range yil! comprises as shown in Fig. 2,a source-of current supply of the three-wire Edison type, which may be 230 volts A. C., including a neutralconductor v minals 'i2 thereof being respectively connected to the conductors |04, |05 and |06 extending and vconnected tothe heating unit i9. Specifically, the stationary contact structure incorporated in the switch 24 comprises the ve stationary contacts ||2, H3, ||4 and H5; while the movable contactstructure incorporated in the switch 24 comprises the five movable contacts |2|, |22, |23, |24 and |25. The stationary contact is connected via the conductor |04 to the left hand extremity of .the heating unit I5; the stationary contacts ||2 and H3 are connected together and via the conductor |05 tothe right hand extremity of the heating unit |9; while the stationary contacts I4 and ||5 are connected together and via the conductor |06 to the mid-tap of the heating unit I9; the heating unit |9 being of the tWosection type including the respective left hand and right hand sections ia and |912. The movable contacts 2| and 22 are connected together and to the outside conductor |02; the movable contacts |23 and |24 are connected together and to the neutral conductor i8! and the movable -contact |25 is connected to the outside conductor |03. Also the conductor |05 is connected to one terminal 95 of the reel mechanism 94; and the other terminal 95 of the reel mechanism 94 is connected to one terminal of the winding 'I9 of the motor '|8; while the other terminal of the Winding 19 is connected to the neutral conductor l0|.

Beforeproceeding with the description of the operation of the heating control circuit in conjunction with the cooking vessel it is noted that when the off push button 68 of the push vbutton switch 24 is operated, as illustrated in Fig. 2, the movable contacts |2| to |25, inclusive, are operated respectively to disengage the individually associated stationary .contacts to l5, inclusive; whereby the circuit connections between the source mentioned and lthe heating unit I9 are open.

When the high push button 63 lis -moved to Vits operated position, the off push button 6|) is returned to vits vunoperated position andthe movable contacts |2|, |22 and |25 are operated into respective engagements with the stationary contacts ||2 and ||5; wherebysthe extremities of the heating sections y|S|a and |9b are connected to the outside conductor1||l2 and the midtap between the heating sections |9a and |9b is connected to the outside conductor |03. Thus the two heating sections |9a and |911 are connected in parallel across the 230 volts source; which position comprises the high heat position of the push button Switch 24.

When the second push button 64 is moved to its `operated position, the high push--button -53 is returned to its unoperated position and themovable contacts 2| and |25 are operated into respective engagements with the stationary contacts and H5; whereby the heating-section |911 is connected across the outside conductors |02 and |03. Thus the heating section -I'Sa Vis connected lacross the 230 volts source; which position comprises the second heat position of the push-button switch 24.

When the third push button 65 is Ymoved to its operated position, the second push button 64 is returned to its unoperated position and the movable contacts |2|, |22 and |24 are operated into respective engagements with the stationary contacts` 2 and ||4; -whereby the extremities of the heating sections VMidland |91) are connected to the outside conductor |02 and the mid-tap Vbetween the heating sections 19a and |9b is connected to the neutral conductor IUI. Thus the two 'heating sections |9a and |9b -are connected in parallel across the Il!) volts source; which position comprises the third heat position of the push button switch v24.

When the low push button-65 is moved toits operated position, the third `push button B5 is returned to its unoperated position and the movable contacts |2| and |24 are operated into respective engagements with the stationary contacts and |4; ywhereby the heating section |9a is connected across the outside conductor |102 and the neutral conductor |0|. `Thus the heating section |9a is connected across the ||0 volts source; which position comprises the low heat position of the push button switch 24. In passing it is noted that the manual operation of the low push button 68 is not in any way interfered with by the bell-crank i5 ccnnecting the low push button 56 to the motor 18.

When the warm push button 6l is moved into its operated position, the low push button 65 is returned to its unoperated position and the movable vcontacts `|2| and |23 are operated into respective engagements with the stationary contacts and I3; whereby the extremities of the heating sections 59a and |91) are connected to the outside conductor IQZ and the neutral conductor |0|. Thus the two heating sections |9a and |91) are connected in series across the 110 volts source; which position comprises the Warm heat positionof the push buttonswitch 24.

When the oi push button 68 is then moved to its operated position, the warm .push button 61 is returned to its unoperated position `and `Vall of the movable contacts |2| to |25, inc1usive, are operated to .disengage the respective Istationary contacts to H5, inclusive, thereby again to interrupt the'circuit connections between the heating unit I9 and the source.

In the foregoing description ofthecircuit control 'positions of the push button switch 24 it should be appreciated that the individual push buttons 63 to 68, inclusive, may be manually operated in 'any desired order or sequence in order to obtain the corresponding settings of the push button switch 24; and that` the mechanical interlock mechanism arranged in the insulating housing 62 positively prevents simultaneous operation of any two of the push buttons. Moreover, the control mechanism arranged in the insulating housing 62 positively insures that all of the movable contacts |2|vv to |25, inclusive, are disengaged` with respect to the associated stationary contacts rto II5, inclusive, between the operationsof any two of the push buttons switch 24; whereby there isk no danger of short-circuits within the insulatingr housing 62 incident to operation of thepush button switch 24 from one of its control positions to the other. when the push button switch 4it occupies high, second, third, low or warm positions the electric lamp 83 is illuminated causing the corresponding operated push buttonsr 63, 64, 65, 66 or 61 to glow in the individual color in order to produce a color indication of the particular operated position of the push button switch 24. This may be accomplished by connecting the electric lamp 93 between the neutral conductor IIiI and the conductor |94, since the movable contact |2| disengages the stationary contact III only when the ofi push button 69 occupies its operated position, as illustrated in Fig. 2. Thus the lamp 83 is illuminated when the off push button occupies its unoperated position, as

Y explained above. y l

Consideringnow the operation of the range IIJ in conjunction with the cooking vessel II, the cock places the food to be cooked into the vessel and then places the vessel II upon the right rear surface heating unit I9. Then the socket 5| is withdrawn from its position in engagement with the trim element 92 and inserted into the recess 49 formed in the outer end of the handgripping portion 46 of the handle 44 in order to establish electrical connection between the plug 59 and the socket 5| and consequently between the control switch 48 and the terminals 95 via the flexible cable 93. placed upon the vessel I I and the high push button 63 of the push button switch 24 is moved to its operated position. Also at this time the thermostatic switch 48 occupies its open position since the associated thermostatic device 41 is cold; whereby the winding 19 of the motor 18 is deenergized. Since the high push button 63 occupies its operated position the sections4 I9a and` |91) of the heating unit I9 are connected in parallel across the 230 volts source causing the heating unit I9 to develop heat at a high rate.

The vessel II and the contained food to be cooked is accordingly heated at a high rate by the heating unit I9; whereby the temperature of the thermostatic device 41 rises fromthe ambient temperature; and when the food contained in the vessel II reaches a temperature of approximately 210 F., the thermostatic device 41 operates the thermostatic switch 48 from its open position into its closed position. At this time the food contained in the vessel has just begun to boil and will continue vigorous boiling shortly unless the rate of heating of the heating unit |9 is reduced; whereby the food contained in the vessel I I may boil over and spill upon the heating unit I9 and the associated cooking top'l3. How- Also in passing it is noted that- At this time the covery 43 is ever, lthis accident isprevented in the present arrangementby virtue of the fact that the ther-y mostatic switch 48 is operated from its open position into its closed position 'at' this time completing a circuit'extending between'the neutral via the winding 19 to one of the terminals 95 and from the outside conductor |02 via the contacts |22 and H2 and the conductor |05 to the other,

terminal the terminals 95 being connected together at the thermostatic switch via the flexible cable 93, the socket 5I, theplug 50 and thel connections disposed in the handle 44.

When .the winding 19 of the motor 18 is thus energized the armature is attracted, causing the heli-crank 15 to be operated through the link 6| so that the low push button 66 is moved into its operated position; whereby the high push button 63 is returned to its unoperated position. When the low push button 66 is thus moved to its operated position and the high push button 63 is returned to its unoperated position, the movable contacts I2I, |22 and |25 are rst operated to disengage the stationary contacts III, II2 and |15, and the movable contacts |2I and |24 are then operated to engage the stationary contacts iii and illl; whereby the circuit for energizing the winding 19 or" the motor 18 is interrupted incident to disengagement of the movable contact E22 and the stationary contact |I2 in order to prevent unnecessary heating of the winding 19 at this time. the movable contact |22 disengages the stationary contact ||2 before the low push button 66 is moved completely into its operated position, the low push buttonl 66 is,nevertheless, moved cornpletely into its operated position due to the kinetic energy of the moving armature 8 of the motorV 1B at this time.` Accordingly, at this time the low push button 66 of the push button switch 24 occupies its operated position causing the com- I pletion of the circuit for supplying low heat to the heat unit I9; whereby the vessel II and the contained `food are heated by the heating unit I9 at the low heating rate in order to prevent undue boiling` of the containedv food. This arrangement is -very advantageous in View ofthe fact that it not only conserves electric energy but it also prevents undue vigorous boiling of the food contained in the vessel and the likelihood of the contained food boiling over upon the heating unit I9 and the associated cooking top I3.

In the operation of the push button switch 24, the high push button 63 `glows red when it occupies its operated position, while the low push button 66 glows green when it occupies its operated position; whereby the distinctive color indications supplement the physical positions of the respective push buttonsl 63 and 66 in order to produce appropriate indications to the cook of the respective actual control positions of the push button switch 24. Thus it will be understood that when the motor 18 is operated by the thermostatic switch 48 carried by the vessel that the'y positions of the respective high and low push buttons 63 and 66 are physically interchanged, and the appropriate two color indicators are interchanged so that there' can never be any doubt in the vmind of the cook concerning operation of the motor 18 and the consequent reduction of the heating rate ofthe heating unit I9 associated in passing it is noted that whilewitnthe vessel. I'lz rromhigh .heatlto lowA heat'.` Alsooupon operating. Ythe `motor T8 inv operating thepush button switch 24v produces a, clicking noisethat is highly advantageous as this clicking of the push button switch 24. produces, an audible` signalv indicating to the cook that the. heating rate-of the heating unit lfassociated withthe. vessel- H- has been changed. from high tolow.,

In the normal operation of the electric range I -thethermostatic switch 48r reduces the heating rate of the heatingunitlg. after the contents ofthe vessel Il isrheated-l to the predetermined cookingcon-dition mentioned and thereafter cooking of the contents of the vessel l l proceeds at the low rate for the required-time interval` depending -upon thecharacter-of the food undergoing the cooking process. After the food contained in the vessel Il has been appropriately cooked, .the cook lmoves the. olif push` button 68 into its operated position; whereby the-push button switch 24 interrupts the heating connections between the heating unit I9 and the-source. At this time the cooklremoves` the detachable socket l` from the cavity 49 providedrin the hand-gripping portionA A16-of the handleV 44 and pulls thereupon in order to cause the reel mechanism 94t to retract the flexible cablev S3 again moving thevsocket 5| into engagement with the outer surface ofthe. trimelement 92. and out of .theVway with respect tothe. cooking top i3. The vessel. Il maythen be. removed from the heating unit I9 utilizing thehand-gripping vportionlofthe handlev 44. Thereafter the contents of the vessel Il may beremoved-to a sui-tabledish and theV vessel Il, asa whole, may bewashed as there isno danger. ofwater enter-- ing the internalstructure ofthe handle v44.

In ,passing it isI noted that since Athe cable 93` terminates in the. socket 5L there .isnohdanger of short-.circuits .or false control ofV themotor 'l8rV should. the socket 5l become disengaged Yfrom theplugll. Also in utilizingtheelectricrrange l0, inY ,COnlunsCtionf-r with-the vessel. .lL there is n0 Possibility of. damagingthecablem by heatingr itsieeethe vcable 9.3 is. iQo. short. tor,.extendro.ver, any Qns 0f the) Surface heating-units: la etc., the Cable, being only lons ,english to reach te.- tWel the fight heed en@ 2.8, Of the backsnlasher I4 and the handle 44, when the vessell I is supported upon the right rear Ysurface heatingunitv I9.

In view of the foregoing it is apparent that there has been provided an improved combination of an electric range anda cooking'vessel, the vessel being selectively operative to'control heating thereof by the associated surface heating unit Vof the electric range. Moreover this arrangement utilizes an improved and simplied control circuit employing a single push button switch that is jointly controlled manually and by the associated electro-responsive vmotor; whereby the heating rate of thesurface heating unit is controlled entirely by the pushv button switch and the push button switch is provided with an indicator arranged to indicate the actual operated position thereof at all times. Finally, the electric range .comprises an improved arrangement forlv facilitating connectiony of the control circuit into the thermostatic switch carried by the cooking vessel.

While there has been described lwhat is atpresent considered to be the preferred embodiment o f the invention, it will be understood that various modifications may belmadetherein, andit is intended to cover-in the` appended claims Cil all such modietons es; fall within ther true the combination comprising. an electro-responsive motor operative to operate said switch into a given one of its positions, an operating circuit for said motor, means responsive to operation of said switch into a predetermined one of its positions for preparing said operating circuit, means including a device governed by said heating unit for closing said prepared operating cir-l cuit, and means responsive to operation of said switch into said given position for opening said operating circuit.

2. In anY electric range including a body supporting a heating unit, a source of current supply, and a'manually operable push button control switch including a plurality of push buttons selectively operative to establish a corresponding plurality of diierent electricalV heating connections between said heating unit and said source in order to effect heating ofv said heating unit at corresponding different heating rates; the combination comprising an electro-responsive motor operative to operate a given one of said push buttons, an operating circuit for said m0- tor, means responsive to operation of a predetermined one of said push buttons for preparing said operating circuit, means including adevice governed by saidv heating unit for closing said prepared operating circuit, and means responsive'to operation of said given push button for opening said operating circuit.

3. In anelectri rangev including a body supporting a heating unitav source ofcurrent supply, and a manually; operable unitary control switch selectively operative from an oi position into respective high and loew positions to complete respective high and llow electrical heating connections between said source and said heating unit in order to effect heating of said heating unit at corresponding high and low heating rates, said switch being' manually operatedfrom said off position into said highposition to initiate heating of'said heating unit; the combination comprising a cooking vessel supported in heat egchange relation'with said heating unit, a device carried Vby said/,vessel and operative in response to apredetermined cooking condition therein, a detachable circuit connector extending between said body and said vessel permitting ready removal of-said vessel-'from said lheating unit, an electro-responsive motor foroperating said switch from saidr high position into said low position, an operating circuit for said motor including saidconnector, means responsive to operation of said switch'into said high position for preparing said operating circuit, means respons'ive to operation of said device for closing said prepared operating circuit, and means responsive to operation' of-'said switch into said low position vfor opening said operating circuit.

4.fIn an electric range including a body supporting a heating unit, a source of current supply, a manually-'operable push button control switch including oifand high and 10W push buttons, and means responsive to operation of said oiT push button for disconnecting said heating unit from said source and responsive to operation of said respective high and low push buttons for completing respective high and low electrical heating connections between said source and said heating unit in order to eiect heating of said heating unit at corresponding high and low heating rates, said high push button being manually operated to initiate heating of said heating unit; the combination comprising a cooking vessel supported in heat exchange relation with said heating unit, a device operatively associated with said cooking vessel and operative in response to a predetermined cooking condition therein, an electro-responsive motor for operating said low push button, an operating circuit for said motor, means responsive to operation of sai-d high push button for preparing said operating circuit, means responsive to operation of said device for closing said prepare-d operating circuit, and means responsive to operation of said low push button for opening said operating circuit.

5. In an electric range including a cooking top, a backsplasher, a heating unit carried by said cooking top, a source of current supply, a manually operable unitary control switch mounted in an opening provided in said backsplasher and selectively operative from the front of said backsplasher into off and high and low positions, and means responsive to operation of said switch from its ofi position into its respective high and low positions for completing respective high and low heating connections between said source and said heating unit in order to effect heating of said heating unit at corresponding high and low heating rates; the combination comprising an electro-responsive motor mounted on the rear of said backsplasher and operative to opcrate said switch into a given one of its positions, an operating circuit for said motor, means responsive to manual operation of said switch into a predetermined one of its positions for preparing said operating circuit, means including a device governed by said heating unit for closing said prepared Operating circuit, and means responsive to operation of said switch into said given one of its positions for opening said operating circuit.

6. In an electric range including a cooking top, a backsplasher, a heating unit carried by said cooking top, a source of current supply,.a mariually operable push button control switch mounted in an opening provided in said backsplasher and including off and high and low push buttons accessible from the front of said backsplasher, and means responsive to operation of said off push button for disconnecting said heating unit from said source and responsive to operation of said respective high and low push buttons for completing respective high and low electrical heating connections between said source and said heating unit in order to eiect heating of said heating unit at corresponding high and low heating rates; the combination comprising an electro-responsive motor mounted on the rear of said backsplasher and operative to operate a given one of said push buttons, an operating circuit for said motor, means responsive to operation of a predetermined one of said push buttons for preparing said operating circuit, means including a device governed by said heating unit for closing said prepared operating circuit, and means responsive to operation of said given one of said push buttons for opening said operating circuit.

WALTER R. ll/.ICDOVVELL.-

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,025,302 Olds Dec. 24, 1935 2,036,049 Ireland Mar. 31, 1936 2,078,675 Lockwood Apr. 27, 1937 2,207,634 Myers et al. July 9, 1940 2,207,871 Myers July 16, 1940 2,222,124 Sherman Nov. 19, 1940 2,385,433 Weber Sept. 25, 1942 2,385,434 Weber Sept. 25, 1942 2,392,635 Bletz Jan. 8, 1946 2,399,423 Bletz Apr. 30, 1946 2,427,444 Colombo Sept. 16, 1947 2,431,904 Andrews Dec. 2, 1947 2,437,555 Rees Mar. 9, 1948 2,485,456 Poole Oct. 18, 1949 FOREIGN PATENTS Number Country Date 7,882 Great Britain of 1910 

